The Spondylitis Association of America estimates that 1 out of 1,250 kids have juvenile spondyloarthritis (JSpA), accounting for approximately 20 percent of all childhood arthritis (swelling of the joints).

Also called juvenile spondylitis, JSpA is a family of rheumatic diseases that cause arthritis and primarily affect the joints along the spine. Spondyloarthritis can also affect other joints of the body, including the shoulders, hips, ribcage, knees, ankles, and toes. Juvenile spondyloarthritis occurs before the age of 16 years and is seen more frequently in boys than in girls.

Types of JSpA Diseases

All juvenile spondyloarthritis subtypes are associated with pain in the spine, neck, and hips, but each JSpA subtype also has its own unique set of signs, symptoms, and areas of inflammation. Symptoms are what a person experiences, such as headache or nausea. Signs are what a doctor can observe or measure, such as a rash or a fever. A doctor that specializes in rheumatology will use the combination of signs and symptoms to diagnose the correct subtype of JSpA.

Types of JSpA include:

• Juvenile ankylosing spondylitis (JAS)
• Juvenile psoriatic arthritis (JPsA)
• Juvenile enteropathic arthritis (JEnA)
• Juvenile reactive arthritis (JReA)
• Juvenile undifferentiated spondyloarthritis (JUSpA)

Juvenile Ankylosing Spondylitis

JAS is a type of arthritis that primarily causes inflammation to the spine and sacroiliac joints (the joints at the pelvis between the sacrum and the ilium). JAS often results in back pain, stooped posture, and enthesitis, which is inflammation of the entheses — the site where muscle, ligaments, and tendons attach to the bone.

Juvenile Psoriatic Arthritis

JPsA is the combination of arthritis and psoriasis, a scaly rash that affects the skin. The result is a combination of pain at the joints and discolored, scaly plaques or sores on the skin. Signs and symptoms of JPsA — such as dactylitis (also called sausage fingers) and thickened or pitted nails — may accompany typical symptoms including lower back pain and morning stiffness.

Juvenile Enteropathic Arthritis

Children with JEnA have signs and symptoms of arthritis, along with those of inflammatory bowel disease (IBD), including diarrhea, abdominal pain, weight loss, and bloody stool.

Juvenile Reactive Arthritis

JReA is often triggered by an infection of the intestinal or genitourinary tract, which includes the urinary and genital organs (e.g., bladder, kidneys, fallopian tubes). This infection likely causes the person’s immune system to become activated and attack the joints. JReA can last anywhere from three to 12 months. Sometimes JReA can be triggered again and the symptoms may return.

Juvenile Undifferentiated Spondyloarthritis

Children and adolescents that have spondyloarthritis symptoms but do not fit the criteria of the other types of JSpA are diagnosed with juvenile undifferentiated spondyloarthritis. People with JUSpA may eventually develop other signs and symptoms that fit the criteria for a different type of spondylitis, resulting in that diagnosis. In other cases, people with the condition may ultimately have a different disease altogether.

What Are the Signs and Symptoms of JSpA?

Common signs and symptoms of JSpA include pain in the lower back due to inflammation. Children or teens usually develop pain or tenderness in the lower part of the body in particular, including the toes, ankles, knees, and hips. Additional signs and symptoms of JSpA usually develop slowly over several months or even years and can include swelling or stiffness in other joints.

The exact signs and symptoms typically depend on the type of JSpA. For example, children with JAS typically have enthesitis. The pain from enthesitis is often the strongest after long periods of inactivity, such as early in the morning or in the middle of the night, and it can result in morning stiffness. Some people with other forms of JSpA also develop a fever, psoriasis, and inflammation of the intestines also known as colitis or Crohn’s disease.

Some children or teens will develop inflammation in their eyes (uveitis), leading to eye redness, pain in the eyes, sensitivity to light, and decreased vision. People with JSpA can experience eye inflammation in one or both eyes at the same time.

Sometimes, people will have symptomatic episodes followed by symptom-free periods of time. The cycle of symptoms is unpredictable, with random flare-ups that can repeat many times. Other children may experience a more severe, long-term progression of the disease.

Read more about the symptoms of spondyloarthritis.

What Causes JSpA?

The exact cause of JSpA is unknown. Many children and teens with JSpA have inherited a gene called HLA-B27, which can increase the susceptibility of developing JSpA. Having HLA-B27 does not mean that the person will develop JSpA, however: Approximately 8 percent of Caucasian children have the HLA-B27 gene and most never go on to develop spondylitis.

How Is JSpA Diagnosed?

The Arthritis Foundation recommends that children with symptoms see a pediatric rheumatologist, which is a doctor who specializes in treating inflammatory arthritis. Diagnosing JSpA may involve a physical exam, blood tests, and imaging tests.

The doctor will typically ask for the child's medical history and search for signs of swelling and tenderness at the joints during the physical examination. Some children may also have eye pain and light sensitivity that the doctor may check for. The doctor may also ask detailed questions about the type of pain, whether physical activity influences the pain, and if there is a family history of arthritis.

The imaging tests include X-rays and MRI to look for inflammation and joint damage. The blood tests usually include testing for the HLA-B27 gene and the erythrocyte sedimentation rate, which is a measure of inflammation in the body.

Read more about diagnosing spondyloarthritis.

What Is the Prognosis for JSpA?

Although there is no cure for JSpA, the disease outcome can vary significantly from person to person and does not always lead to chronic disease. Some people with JSpA go months or years without symptoms, whereas others will need long-term treatment to manage their disease — nearly 20 percent of those with JSpA develop ankylosing spondylitis as an adult. It is essential to get the right diagnosis as early as possible to begin the correct treatment.

Talk With Others Who Understand

MySpondylitisTeam is the social network for people with spondylitis and their loved ones. On MySpondylitisTeam, more than 67,000 members come together to ask questions, give advice, and share their stories with others who understand life with ankylosing spondylitis.

Does your child have juvenile spondylitis? Share your experience in the comments below, or start a conversation by posting on MySpondylitisTeam.